Radiation has been employed to image and treat tumorous tissue. In radiation therapy, a high energy beam is applied from an external source towards the patient. The external source, which may be rotating (as in the case for arc therapy), produces a collimated beam of radiation that is directed into the patient to the target site. The dose and placement of the dose must be accurately controlled to ensure that the tumor receives sufficient radiation, and that damage to the surrounding healthy tissue is minimized.
Sometimes, in a radiation treatment procedure, a plurality of treatment sessions may be performed. In each treatment session, a radiation source may be placed at one or more prescribed gantry angles to thereby deliver radiation beam towards a target tissue from certain prescribed angles. As a result of delivering radiation towards the target tissue from a plurality of different angles, a sufficient radiation dose may be delivered to the target tissue to thereby treat the target tissue, while surrounding healthy tissue may be protected.
In some cases, before a radiation treatment session is performed, an image of the target region may be obtained to verify the shape and location of the target region. After a treatment session is performed, an image of the target region may also be obtained again to verify that the dosage was correctly delivered during the treatment session. Inventor of the subject application determines that it is desirable to have an efficient technique for obtaining reconstructed image during a treatment session.